The last miner from Technobit that I reviewed was
HEX4M, a good board that later was transformed to an enclosed miner with two of these boards and custom cooling -
2HEX4M. Now I'm going to present you the next enclosed solution from Technobit -
HEX4RBox based on the latest 28nm RockerBox ASIC chip from Spondoolies Tech.
The device looks identical with Antminer's S3, maybe slightly longer, to be precise: D 410mm; W 150mm; H 130mm
Specification and Performance:
The board is equipped with 4 Rockerbox ASICs and according to the specification each chip is rated at 200GH with a wide range of overclock/downclock options. On the other side Technobit advertise the miner as 850GH, and here is my best result from these 4
More than 880GH is a very impressive result and as you can see the chips are at 800mV - the upper limit in the Spondoolies Specs. Now lets make some more tests and see what is the efficiency of the board:
The power supply used for the tests is Delta DPS 2000BB with 90-92% eff. In my previous reviews I used to calculate boards efficiency but since all major manufactures publish at WALL efficiency I made the switch and that's what the eff column represents. Keep in mind that your results may vary depending on your power supply.
As you can see from the chart above at maximum hashrate the efficiency is terrible by today's standards, but with lower settings things are looking better. You can play around with the settings, if some of the chips is getting low on power you will see increase in HW errors, a good indicator for your max freq. My personal best setting atm is 1040/760mV, I was trying to go lower than 690mV but apparently the fw doesn't support it and the miner just wont's start, at this voltage the performance is good and I believe that with some boards you can achieve better freq/hashrate.
Cooling:
The enclosed miner is cooled by two big SUNON fans in a push/pull configuration
PMD1212PMB1-ASize / Dimension: 120mm L x 120mm H x 38mm W
Air Flow: 190.0 CFM (5.38m³/min)
Speed: 4200 RPM
Power: 19.2W
Noise: 54 dB(A)
Let me get this straight this is LOUD, no really it is and in any way it is not suitable for home usage at least not by my understandings. Luckily there is a realativly easy way to fix this, with a simple mod. You can just connect the two fans in series, that way the voltage is divided and they run at nearly half speed, by doing so you also have to keep the settings lower or do some more optimizations (keep reading).
Heat is dissipated from the chips by a huge heatsink on the top and thinner one on the bottom of the board helping also to cool down volt regulators. As you can see from the photos there is a lot of space and the fans are blowing out cold air that just passes by. Here are some tweaks, I changed the thermal compound with Arctic Cooling MX-4, but you can use your favorite, also very important step is to narrow the airflow by blocking empty space on top and side near the usb port. I did that with plastic cable tray holding in place by 3M double sided tape. You can also tape the 3 cable holes or use rubber grommet plugs that have pie slice cut flaps in them allow you to route the cables. With these mods and fans at half speed I can run the board at any speed without an issue. Things that can be improved by technobit in future projects, at least the airflow can be better and they can put some rubber grommets in the holes.
Really the top heatsink is an overkill, with this massive copper plate bolted into the aluminum. Even that there are 4 chips cooled by a single plate I don't recommend using thermal pads.
Pricing:There is not much to say here. ATM You can choose from:
Technobit HEX4R - 850GH - 365$ (0.43$/GH)
Spondoolies SP20 - 1700GH - 659$ (0.38$/GH)
Bitmain Antminer S5 - 1155GH/s - 418$ (0.36$/GH) (just released)
I assume that Technobit will update their price, corresponding to new offers from Spondo and Bitmain. In any way as a resident of the EU I prefer to buy within the union - cheaper shipping and no issues with Customs and taxes.
Host device and Software:As all other products from Technobit this is no exception, you need a host device to control the board that can be:
1. Take one TP-Link TL-MR3020 Router and flash it with the firmware from Technobit's website. Here is a great
tutorial by Zich. You can also order it directly from them at slightly higher price, but pre-flashed and ready to rock. If you plan to use the router you will also need USB hub.
2. Windows based PC with patched version of cgminer that supports the HEX boards, more info how to run it here:
CGMINER Windows build for TECHNOBIT's Boards 3. On a Linux based PC it will best to just compile cgminer with the latest patch from Technobit or download my build for Ubuntu x64
(link by request)4. You can also use Raspberry Pi as a host device
Here is how to apply patch 0.4.0 and compile cgminer on linux host:
git clone https://github.com/ckolivas/cgminer.git
cd cgminer
wget https://dl.dropboxusercontent.com/u/8082585/Technobit/rev_9afd0a216a0f95adb650e4818f24af1a61ad837d.patch
git checkout 9afd0a216a0f95adb650e4818f24af1a61ad837d
patch < rev_9afd0a216a0f95adb650e4818f24af1a61ad837d.patch
./autogen.sh --enable-hexminerr
make
cgminer.conf settings needed:
"hexminerr-asic-diff" : "5",
"hexminerr-pic-roll" : "120",
"hexminerr-chip-mask" : "255",
"hexminerr-voltage" : "760",
"hexminerr-options" : "4:1040",
Pros:- Reasonably priced
- Software voltage control
- Good overclock/undervolt capabilities
Cons:- No thermal sensor
- Host controller is needed
- LOUD
Conclusion:The efficiency of the board is not so good compared to SP20, Guy from spondoolies said that later batches are with better eff so that maybe one of the reasons. Other factor to blame is probably low efficient DC2DC regulators, also keep in mind that with SP20 the software can set voltage and freq to each chip independently. In any way this device is a step in the right direction for Technobit and I can't wait to test their 1 chip version called DICE.
Full gallery can be found here:
http://imgbox.com/g/8sLfvmvAqFbest
2GOOD
